1. Field of the Invention
The present invention relates to a disk cartridge. More particularly, the present invention is concerned with a disk cartridge which provides improved cleanability of its disk by a cleaning member, and which is further capable of maintaining an appropriate torque of the disk resulting from the rubbing friction with the cleaning member.
2. Description of the Related Art
Generally disk cartridges have a structure wherein a cleaning member for cleaning a magnetic disk is disposed on the inner surface of the cartridge body. In addition, the cartridge body comprises top and bottom shells, the inner surface of at least one of which has a cleaning member attached thereon.
Such a cleaning member is composed of a fibrous sheet, and is rubbed in a sliding manner against the surface of the magnetic disk for the collection of dust, etc. from the surface. Further, in the case of disk cartridges for 3.5-inch magnetic disks, a lifter is installed between the cleaning member and the inner surface of the cartridge body. The lifter serves to push against part of the cleaning member in a curved manner toward the surface of the magnetic disk to allow the curved-out portion to satisfactorily clean the surface of the magnetic disk.
In the disk cartridges of the prior art, however, the density of the cleaning member is a relatively high density of about 0.20 g/cm.sup.3 at a load of 4.4 gf/cm.sup.2, and thus the torque applied to the magnetic disk tends to change considerably due to the variations in the thickness of the member.
Furthermore, the most probable pressing force of around 4-5 gf/cm.sup.2 of the cleaning member on the magnetic disk through the use of a lifter or the like for improving the cleaning efficacy may cause an excessive torque to be applied to the magnetic disk. For this reason, the thickness of the cleaning member has been reduced to reduce contact of the sections of the lifter other than that on which the lifter is installed, thereby resulting in improvement of the cleaning efficacy of the lifter-installed section alone. There are some cases, however, where the restorability of the lifter is reduced with the passage of time, and thus the cleaning performance of the cleaning member is correspondingly reduced.
In addition, with warping of the shells, etc., the pressing force of the cleaning member on the magnetic disk sometimes reaches approximately 10 gf/cm.sup.2. This produces a drawback with rechargeable word processors and the like in that much power is consumed during operation, resulting in an accelerated draining of the battery.